The Telegraph
Thursday , July 31 , 2014
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Storm alert on Dreamliners

New Delhi, July 30: Boeing has advised Air India to avoid flying Dreamliners close to thunderstorms because of the risk of ice formation on the engines, the Centre told Parliament today even as airline officials said the problem wouldn’t hinder operations.

“Boeing has issued an advisory to Air India to avoid flying the (Dreamliner) aircraft near high-level thunderstorms due to an increased risk of icing on the General Electric engines,” minister of state for civil aviation G.M. Siddeshwara said in reply to a question in the Lok Sabha.

Air India mainly uses its new Dreamliners — the first arrived less than two years ago — for long-haul flights to Europe, the US and Australia, besides select domestic destinations. But snags have hit the planes often, forcing the airline to ground them and turn to Boeing to fix the glitches.

Ice crystals on the engine, especially behind the main propeller, can cause a brief loss of thrust (engine power). “In view of this, Boeing has modified operating procedures. The new procedures fully comply with all standards and do not compromise flight safety,” Siddeshwara said.

US plane maker Boeing issued the advisory last week saying the Dreamliners — models 747-8 and 787 — should not be flown at high attitudes within 50 nautical miles (93km) of thunderstorms as such weather systems may have ice crystals.

Icing occurs when water cooled to freezing point comes into contact with an aircraft, causing possible loss of thrust that could stall it and result in loss of control.

Japan Airlines, Lufthansa, United Airlines and Cathay Pacific — all of which have Dreamliners — have also been advised the precaution.

Air India officials insisted the problem hadn’t hit operations. “All airlines using this aircraft have received an advisory from Boeing. We have modified our operations accordingly and are not flying the planes on routes more susceptible to big thunderstorms,” said an airline spokesperson.

Asked how such planes avoided coming in the path of thunderstorms, the official said: “The airline has weather reports. Also, such thunderstorms happen at certain levels (altitudes). The pilot charts out a deviation. None of our Dreamliner operations has been affected by this problem.”

According to officials of General Electric (GE), which supplies Boeing engines for some Dreamliners, the problem is on the rise.

“The aviation industry is experiencing a growing number of ice-crystal encounters in recent years, particularly in tropical regions of the world, as the number of large commercial airliners has grown. However, all the planes (that faced the problem) landed at their destinations safely,” a GE official said.

GE and Boeing are working on modifications to eliminate the problem, the GE official said. Some Dreamliners are powered by Rolls-Royce engines.